Curb bulbs are a form of roadway narrowing at intersections that reduce the street width from curb to curb. They shorten crossing distances for pedestrians and draw attention to pedestrians via raised peninsulas. They also tighten the curb radii at the corners, reducing the speeds of turning vehicles. They can be used to create protected on-street parking bays.

Curb bulbs come in a wide variety of sizes and typically result in speed decreases of 7%. They are easily combined with a raised intersection or raised mid-block crosswalk. Curb bulbs placed opposite one another mid-block create a "choker," which can result in more significant speed reduction.